C++ goto Statement — Syntax and Alternatives | Tutorials Logic

What is goto?

The goto statement transfers control unconditionally to a labeled statement within the same function. It is one of the oldest control flow mechanisms inherited from C.

Avoid goto in modern C++. It makes code hard to read, debug, and maintain. Use structured alternatives: break, continue, return, exceptions, or helper functions instead.

goto Syntax and Example

#include <iostream>
using namespace std;

int main() {
    int i = 0;

loop:  // label
    if (i < 5) {
        cout << i << " ";
        i++;
        goto loop;  // jump back to label
    }
    cout << endl;  // 0 1 2 3 4

    // goto to skip code
    int x = 10;
    if (x > 5) goto skip;
    cout << "This won't print" << endl;

skip:
    cout << "Jumped here with goto" << endl;

    return 0;
}

// Note: goto cannot jump over variable initializations
// int y = 5;
// goto label;
// int z = 10;  // ERROR: jump over initialization
// label: ...;

#include <iostream>
using namespace std;

// The ONLY somewhat acceptable use of goto in C++:
// breaking out of deeply nested loops
// (even then, prefer a helper function)

bool findInMatrix(int matrix[][3], int rows, int target) {
    for (int i = 0; i < rows; i++) {
        for (int j = 0; j < 3; j++) {
            if (matrix[i][j] == target) {
                return true;  // BETTER: use return instead of goto
            }
        }
    }
    return false;
}

int main() {
    int matrix[3][3] = {{1,2,3},{4,5,6},{7,8,9}};

    // Structured approach - no goto needed
    if (findInMatrix(matrix, 3, 5)) {
        cout << "Found 5 in matrix" << endl;
    }

    // Simple loop - use for/while, not goto
    for (int i = 0; i < 5; i++) {
        cout << i << " ";
    }
    cout << endl;

    return 0;
}

Key Takeaways

goto transfers control to a labeled statement - it is generally considered bad practice.
goto can only jump within the same function - it cannot jump between functions.
The main valid use case for goto in C++ is breaking out of deeply nested loops.
Modern C++ alternatives to goto: break with labels, exceptions, or refactoring into functions.
goto can skip variable initialization - this causes a compile error in C++.
Most coding standards (Google, LLVM, etc.) prohibit or strongly discourage goto.