Нужно создать setting.json и там прописать вот это

{
  "C_Cpp_Runner.cCompilerPath": "C:/MinGW/bin/gcc.exe",
  "C_Cpp_Runner.cppCompilerPath": "C:/MinGW/bin/g++.exe",
  "C_Cpp_Runner.debuggerPath": "C:/MinGW/bin/gdb.exe",
  "C_Cpp_Runner.cStandard": "",
  "C_Cpp_Runner.cppStandard": "",
  "C_Cpp_Runner.msvcBatchPath": "",
  "C_Cpp_Runner.warnings": [
    "-Wall",
    "-Wextra",
    "-Wpedantic"
  ],
  "C_Cpp_Runner.enableWarnings": true,
  "C_Cpp_Runner.warningsAsError": false,
  "C_Cpp_Runner.compilerArgs": [],
  "C_Cpp_Runner.linkerArgs": [],
  "C_Cpp_Runner.includePaths": [],
  "C_Cpp_Runner.includeSearch": [
    "*",
    "**/*"
  ],
  "C_Cpp_Runner.excludeSearch": [
    "**/build",
    "**/build/**",
    "**/.*",
    "**/.*/**",
    "**/.vscode",
    "**/.vscode/**"
  ]
}

Тогда уже вроде должны быть не кракозябры