× Home
Next Lec → ← Previous Lec

If Else Control Statements in C

It is used to perform operations according to a trueness or falseness of some condition.

Sometimes we want a set of instructions to be executed if certain condition is satisfied and an entirely different set of instructions to be executed if the condition does not fulfil. This kind of situation is dealt in C language using a decision control instruction.

Types of If statements

Syntax for if

                        

                            if(condition){
                                //if true
                            }

Syntax for if else

                        

                            if(condition){
                                    //if true
                                }
                                else {
                                    //if not true
                            }

Syntax for if else if ladder

                        

                            if(condition 1){
                                    //if true
                                }
                                else if(condition 2{
                                    //if true
                                }
                                .
                                .
                                .
                                else {
                                    // no condition is true
                            }

Example code

if else

                            

                                    #include <stdio.h>
                                    int main()
                                    {
                                        int age=0;
                                        printf("Enter your age\n");
                                            scanf("%d",&age);
                                        if(age>=18){
                                            printf("You are able to vote");
                                        }
                                        else {
                                            printf("You are not able to vote \n try next year");
                                        }
                                        return 0;
                                    }

if else if

                            

                                    #include <stdio.h>
                                    int main()
                                    {
                                        int age=0;
                                        printf("Enter your age\n");
                                        scanf("%d",&age);
                                        if(age>=18){
                                            printf("You are able to vote");
                                        }
                                        if else(age>=10){
                                            printf("you can apply for voter id but can't vote yet");
                                        }
                                        else {
                                            printf("You are not able to vote \n try next year");
                                        }
                                      r eturn 0;
                                    }

Practice

                            

                                    #include <stdio.h>
                                    int main(){
                                        int val;
                                        printf("Put 1 if you have passed both exam \n put 2 if you have passed only maths \n put 3 is you have only passed science: ");
                                        scanf("%d",&val);
                                        if(val == 1){
                                            printf("Congratulations you have passed both the exams your gift is Rs. 45");
                                        }
                                        else if(val == 2){
                                            printf("Congratulations you have passed only in maths exam your gift is Rs. 15");
                                        }
                                        else if(val == 3){
                                            printf("Congratulations you have passed only in science exam your gift if Rs. 15");
                                        }
                                        else{
                                            printf("Your input is incorrect \n Put 1 if you have passed both exam \n put 2 if you have passed only maths \n put 3 is you have only passed science: ");
                                            scanf("%d",&val);
                                        }
                                        return 0;
                                    }