goto Statement in C

The C goto statement is a jump statement which is sometimes also referred to as an unconditional jump statement. The goto statement can be used to jump from anywhere to anywhere within a function. 

Syntax:

Syntax1      |   Syntax2
----------------------------
goto label;  |    label:  
.            |    .
.            |    .
.            |    .
label:       |    goto label;

In the above syntax, the first line tells the compiler to go to or jump to the statement marked as a label. Here, the label is a user-defined identifier that indicates the target statement. The statement immediately followed after ‘label:’ is the destination statement. The ‘label:’ can also appear before the ‘goto label;’ statement in the above syntax. 

Flowchart of goto Statement in C

Below are some examples of how to use a goto statement.

Examples:

Type 1: In this case, we will see a situation similar to as shown in Syntax1 above. Suppose we need to write a program where we need to check if a number is even or not and print accordingly using the goto statement. The below program explains how to do this: 

C

// C program to check if a number is
// even or not using goto statement
#include <stdio.h>

// function to check even or not
void checkEvenOrNot(int num)
{
    if (num % 2 == 0)
        // jump to even
        goto even;
    else
        // jump to odd
        goto odd;

even:
    printf("%d is even", num);
    // return if even
    return;
odd:
    printf("%d is odd", num);
}

int main()
{
    int num = 26;
    checkEvenOrNot(num);
    return 0;
}

Output:

26 is even

Type 2: In this case, we will see a situation similar to as shown in Syntax2 above. Suppose we need to write a program that prints numbers from 1 to 10 using the goto statement. The below program explains how to do this. 

C

// C program to print numbers
// from 1 to 10 using goto statement
#include <stdio.h>

// function to print numbers from 1 to 10
void printNumbers()
{
    int n = 1;
label:
    printf("%d ", n);
    n++;
    if (n <= 10)
        goto label;
}

// Driver program to test above function
int main()
{
    printNumbers();
    return 0;
}

Output:

1 2 3 4 5 6 7 8 9 10

Disadvantages of Using goto Statement

• The use of the goto statement is highly discouraged as it makes the program logic very complex.
• The use of goto makes tracing the flow of the program very difficult.
• The use of goto makes the task of analyzing and verifying the correctness of programs (particularly those involving loops) very difficult.
• The use of goto can be simply avoided by using break and continue statements.