Run C Online

main.c

#include <stdio.h>

int main() {
    printf("Hello from C!\n");
    for (int i = 1; i <= 5; i++) {
        printf("  %d factorial = ", i);
        int f = 1;
        for (int j = 1; j <= i; j++) f *= j;
        printf("%d\n", f);
    }
    return 0;
}

Output

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About C

C is the foundation of modern computing. From operating systems like Linux to embedded systems and IoT devices, C provides unmatched control over hardware and memory. It remains essential for systems programming and performance-critical applications.

Our sandbox runs GCC 14 with full C23 standard support.

Sandbox Features

Secure execution with Docker + gVisor isolation
GCC 14 with C23 standard support
Up to 300s execution time (Pro tier)
Stdin support for interactive programs
REST API for programmatic access
No setup or installation required

Use C with stateful sessions

Open a session once, then call execute repeatedly. Files and installed packages persist between runs, which is ideal for code interpreters and iterative agents.

# 1. Create a session
curl -X POST https://api.sandboxapi.dev/v1/sessions \
  -H "X-RapidAPI-Key: $KEY" \
  -d '{"language":"c","idle_ttl":300}'
# → {"id":"sess_abc","language":"c",...}

# 2. Execute — first call
curl -X POST https://api.sandboxapi.dev/v1/sessions/sess_abc/execute \
  -H "X-RapidAPI-Key: $KEY" \
  -d '{"code":"int x = 42; printf(\"%d\\n\", x);"}'

# 3. Execute again — state carries over
curl -X POST https://api.sandboxapi.dev/v1/sessions/sess_abc/execute \
  -H "X-RapidAPI-Key: $KEY" \
  -d '{"code":"// Note: C is compiled — sessions persist files, not REPL state"}'

Note: C is a compiled language. Sessions persist installed packages and files on disk, but variable state does not carry between calls. Write intermediate state to disk when you need continuity.

Read the sessions docs →

About C

Sandbox Features

Use C with stateful sessions

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