updating visual studio

.github/workflows/vs17-arm-ci.yml

diff --git a/.github/workflows/vs17-arm-ci.yml b/.github/workflows/vs17-arm-ci.yml
index 9eef012..e1c6f77 100644
--- a/.github/workflows/vs17-arm-ci.yml
+++ b/.github/workflows/vs17-arm-ci.yml
@@ -10,8 +10,8 @@
       fail-fast: false
       matrix:
         include:
-          - {gen: Visual Studio 17 2022, arch: ARM64, cfg: Release}
-          - {gen: Visual Studio 17 2022, arch: ARM64, cfg: Debug}
+          - {gen: Visual Studio 18 2026, arch: ARM64, cfg: Release}
+          - {gen: Visual Studio 18 2026, arch: ARM64, cfg: Debug}
     steps:
       - name: checkout
         uses: actions/checkout@v6.0.2

.github/workflows/vs17-ci.yml

diff --git a/.github/workflows/vs17-ci.yml b/.github/workflows/vs17-ci.yml
index 39a5bd4..cdee064 100644
--- a/.github/workflows/vs17-ci.yml
+++ b/.github/workflows/vs17-ci.yml
@@ -10,10 +10,10 @@
       fail-fast: false
       matrix:
         include:
-          - {gen: Visual Studio 17 2022, arch: Win32, cfg: Release}
-          #- {gen: Visual Studio 17 2022, arch: Win32, cfg: Debug}
-          - {gen: Visual Studio 17 2022, arch: x64, cfg: Release}
-          - {gen: Visual Studio 17 2022, arch: x64, cfg: Debug}
+          - {gen: Visual Studio 18 2026, arch: Win32, cfg: Release}
+          #- {gen: Visual Studio 18 2026, arch: Win32, cfg: Debug}
+          - {gen: Visual Studio 18 2026, arch: x64, cfg: Release}
+          - {gen: Visual Studio 18 2026, arch: x64, cfg: Debug}
     steps:
       - name: checkout
         uses: actions/checkout@v6.0.2

.github/workflows/vs17-clang-ci.yml

diff --git a/.github/workflows/vs17-clang-ci.yml b/.github/workflows/vs17-clang-ci.yml
index 25a54b8..27fc268 100644
--- a/.github/workflows/vs17-clang-ci.yml
+++ b/.github/workflows/vs17-clang-ci.yml
@@ -10,10 +10,10 @@
       fail-fast: false
       matrix:
         include:
-          - {gen: Visual Studio 17 2022, arch: Win32, cfg: Release}
-          - {gen: Visual Studio 17 2022, arch: Win32, cfg: Debug}
-          - {gen: Visual Studio 17 2022, arch: x64, cfg: Release}
-          - {gen: Visual Studio 17 2022, arch: x64, cfg: Debug}
+          - {gen: Visual Studio 18 2026, arch: Win32, cfg: Release}
+          - {gen: Visual Studio 18 2026, arch: Win32, cfg: Debug}
+          - {gen: Visual Studio 18 2026, arch: x64, cfg: Release}
+          - {gen: Visual Studio 18 2026, arch: x64, cfg: Debug}
     steps:
       - name: checkout
         uses: actions/checkout@v6.0.2

.github/workflows/vs17-cxx20.yml

diff --git a/.github/workflows/vs17-cxx20.yml b/.github/workflows/vs17-cxx20.yml
index dda7afc..bc9e11e 100644
--- a/.github/workflows/vs17-cxx20.yml
+++ b/.github/workflows/vs17-cxx20.yml
@@ -10,10 +10,10 @@
       fail-fast: false
       matrix:
         include:
-          - {gen: Visual Studio 17 2022, arch: Win32, cfg: Release}
-          - {gen: Visual Studio 17 2022, arch: Win32, cfg: Debug}
-          - {gen: Visual Studio 17 2022, arch: x64, cfg: Release}
-          - {gen: Visual Studio 17 2022, arch: x64, cfg: Debug}
+          - {gen: Visual Studio 18 2026, arch: Win32, cfg: Release}
+          - {gen: Visual Studio 18 2026, arch: Win32, cfg: Debug}
+          - {gen: Visual Studio 18 2026, arch: x64, cfg: Release}
+          - {gen: Visual Studio 18 2026, arch: x64, cfg: Debug}
     steps:
       - name: checkout
         uses: actions/checkout@v6.0.2

tests/fast_int.cpp

diff --git a/tests/fast_int.cpp b/tests/fast_int.cpp
index 52ad5a6..10e7dcf 100644
--- a/tests/fast_int.cpp
+++ b/tests/fast_int.cpp
@@ -1614,7 +1614,7 @@
       uint64_t mag = neg ? (~uint64_t(value) + 1) : uint64_t(value);
       std::string s;
       if (mag == 0) {
-        s = "0";
+        s += '0';
       }
       while (mag != 0) {
         s += digit_to_char(int(mag % uint64_t(base)));